CVE-2022-49688 afs: Fix dynamic root getattr

Medium 5.5 Published Updated

A null pointer dereference in the Linux kernel AFS filesystem allows local attackers to cause a system crash by stat-ing a dynamic root directory.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Local or same network only
Victim action needed
Not needed
Fix
Available

What is CVE-2022-49688?

CVE-2022-49688 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

afs: Fix dynamic root getattr

The recent patch to make afs_getattr consult the server didn't account for the pseudo-inodes employed by the dynamic root-type afs superblock not having a volume or a server to access, and thus an oops occurs if such a directory is stat'd.

Fix this by checking to see if the vnode->volume pointer actually points anywhere before following it in afs_getattr().

This can be tested by stat'ing a directory in /afs. It may be sufficient just to do "ls /afs" and the oops looks something like:

BUG: kernel NULL pointer dereference, address: 0000000000000020 ... RIP: 0010:afs_getattr+0x8b/0x14b ... Call Trace: <TASK> vfs_statx+0x79/0xf5 vfs_fstatat+0x49/0x62

Weakness: CWE-476

Which versions are affected by CVE-2022-49688?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-49688?

Apply the vendor's patch.

Is CVE-2022-49688 being exploited?

There is no known exploitation of CVE-2022-49688 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as DEBIAN-CVE-2022-49688, GHSA-gq92-c2vh-pqwx, UBUNTU-CVE-2022-49688.

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